bf864f6c-12b0-11e0-81a7-a16102e577a5Geologic Map of the Eastern Eagletail Mountains, Maricopa, La Paz, and Yuma Counties, ArizonaSpencer, E. J.Gilbert, W.G.Richard, M.S.Arizona Geological SurveyThe area described in this study includes the eastern Eagletail Mountains, Maricopa, La Paz, and
Yuma counties, Arizona. The study area encompasses all of the Eagletail Mountains East Quadrangle
(1:24,000) and is partially within the Eagletail Mountains Wilderness Area (Figure 1). Bedrock in this
area consists largely of pre-Tertiary granitoid rocks of probable Jurassic age that are intruded by
numerous Tertiary dikes and overlain by an extensive sequence of Miocene silicic volcanic rocks and
subordinate mafic and intermediate volcanic units (plate 1). Sources of data are shown in Figure 2, rockunit
correlations and relative ages are shown in Figure 3, and map symbols are shown in Table 1.
The area was mapped in part with funds provided to the Arizona Geological Survey by the U.S.
Geological Survey COGEOMAP program, contract #14-08-0001-A0872. Field work was carried out by
the authors in February, 1992. The views and conclusions contained in this document are those of the
authors and should not be interpreted as necessarily representing the official policies, either expressed
or implied, of the U.S. Government.2013-07-26T16:00:53datasetalluviumbasaltcalcitedikesdioritefelsic volcanicFrenchman Mine Plutongneissgranitoidhematitemafic volcanicsmalachitemylonitespegmatitevolcanicsJurassicMesozoicMioceneProterozoicQuaternaryTertiaryArizonaBasin and Range ProvinceEagletail Mountains Wilderness AreaEastern Eagletail MountainsGranite MountainLa Paz CountyMaricopa CountyYuma CountyEnglish-113.375 33.375-113.25 33.5-113.375 33.375-113.25 33.5